THE UN’s climate change chief, Rajendra Pachauri, has acknowledged a 17-year pause in global temperature rises, confirmed recently by Britain’s Met Office, but said it would need to last “30 to 40 years at least” to break the long-term global warming trend.

Dr Pachauri, the chairman of the UN’s Intergovernmental Panel on Climate Change, said that open discussion about controversial science and politically incorrect views was an essential part of tackling climate change.

In a wide-ranging interview on topics that included this year’s record northern summer Arctic ice growth, the US shale-gas revolution, the collapse of renewable energy subsidies across Europe and the faltering European carbon market, Dr Pachauri said no issues should be off-limits for public discussion.

In Melbourne for a 24-hour visit to deliver a lecture for Deakin University, Dr Pachauri said that people had the right to question the science, whatever their motivations.

“People have to question these things and science only thrives on the basis of questioning,” Dr Pachauri said.

He said there was “no doubt about it” that it was good for controversial issues to be “thrashed out in the public arena”.

Dr Pachauri’s views contrast with arguments in Australia that views outside the orthodox position of approved climate scientists should be left unreported.

Unlike in Britain, there has been little publicity in Australia given to recent acknowledgment by peak climate-science bodies in Britain and the US of what has been a 17-year pause in global warming. Britain’s Met Office has revised down its forecast for a global temperature rise, predicting no further increase to 2017, which would extend the pause to 21 years.